Brake rotor and tone ring assembly

ABSTRACT

A wheel assembly includes a wheel hub and brake rotor that rotate about an axis. The brake rotor includes a first mount interface for attachment to the wheel hub and a second mount interface for attachment to a tone ring. The first and second mount interfaces are independent of each other. The first mount interface comprises a first plurality of apertures that receive a first set of fasteners to secure the brake rotor to the wheel hub. The second mount interface comprises a second plurality of apertures that receive a second set of fasteners to secure the tone ring to the brake rotor.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/145,407, which was filed Jun. 3, 2005.

TECHNICAL FIELD

The subject invention relates to a brake rotor that provides independentwheel hub and tone ring attachment interfaces such that a tone ring isindependently removable from the brake rotor without requiring removalof the brake rotor from the wheel hub, and such that the brake rotor isremovable from the wheel hub without have to remove the tone ring fromthe brake rotor.

BACKGROUND OF THE INVENTION

A wheel assembly includes a brake rotor that is attached to a wheel hubfor rotation about an axis. When utilized with an anti-lock brakesystem, a tone ring is often attached to a rotating wheel component,such as the brake rotor for example, to form part of a wheel speedsensor. Due to packaging constraints, it is often difficult to leave thetone ring attached to the brake rotor while still providing access toattachment bolts that are used to attach the brake rotor to the wheelhub.

In one known configuration, a single set of fasteners is used to attachthe tone ring, brake rotor, and wheel hub together. In order to removethe brake rotor from the wheel hub for service, the tone ring must beremoved from the brake rotor. Further, in order to remove the tone ringfrom the brake rotor for service, the brake rotor must be removed fromthe wheel hub. In either situation, labor costs and downtime areincreased as a result of additional wheel components having to beremoved from the wheel assembly.

One known attempted solution has been to provide a brake rotor with anintegrally formed tone ring. This solution has several disadvantages.One disadvantage with this solution is that both the brake rotor andtone ring are formed from a common material. In order to reduce materialcosts and component weight, it is often desirable to form the tone ringand brake rotor from different materials. Another disadvantage is thatif one component is damaged, i.e. if a portion of the brake rotor or aportion of the tone ring is damaged, then both components have to bereplaced. This significantly increases service costs.

Thus, there is a need for a brake rotor, tone ring, and wheel hubconfiguration that allows for independent removal of the variouscomponents without requiring removal of all of the components.

SUMMARY OF THE INVENTION

A wheel assembly includes a tone ring and brake rotor, which are mountedto a wheel hub for rotation about an axis. The brake rotor is mounted tothe wheel hub at a first mount interface and the tone ring is mounted tothe brake rotor at a second mount interface that is independent from thefirst mount interface. The subject invention provides that the brakerotor is removable from the wheel hub while the tone ring remainsattached to the brake rotor, and provides that the tone ring isremovable from the brake rotor while the brake rotor remains attached tothe wheel hub.

In one disclosed embodiment, first mount interface of the brake rotorcomprises a first plurality of openings for receiving a first set offasteners to attach the brake rotor to the wheel hub. The second mountinterface comprises a second plurality of apertures for receiving asecond set of fasteners to independently attach the tone ring to thebrake rotor.

This wheel assembly provides several advantages including providingseparate pieces for the tone ring and brake rotor, which allows the tonering to be fabricated from a different material than the brake rotor.Also, as described above, access is provided to the first plurality ofapertures to remove the brake rotor from the wheel hub without having toremove the tone ring from the brake rotor. In addition, removal of thetone ring is possible without having to remove the brake rotor from thewheel hub. This significantly facilitates maintenance, inspection, andcleaning operations for the various components. These and other featuresof the present invention can be best understood from the followingspecification and drawings, the following of which is a briefdescription.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a wheel hub, brake rotor, and tone ringassembly incorporating the subject invention.

FIG. 2 is a front view of the brake rotor shown in FIG. 1.

FIG. 3 is a cross-sectional view of the brake rotor of FIG. 2 asindicated by line 3-3 in FIG. 2.

FIG. 4 is a front view of the tone ring shown in FIG. 1.

FIG. 5 is a cross-sectional view of the tone ring of FIG. 4 as indicatedby line 5-5 in FIG. 4.

FIG. 6 is a side view of an assembly of the brake rotor and the tonering.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A hub and rotor assembly for a vehicle wheel is shown generally at 10 inFIG. 1. The hub and rotor assembly 10 includes a wheel hub 12, a brakerotor 14, and a tone ring 16. The tone ring 16 forms part of a wheelspeed sensor for an anti-lock braking system. The hub and rotor assembly10 can be used with any type of anti-lock braking system. The operationof an anti-lock brake system and wheel speed sensors are well known andwill not be discussed in further detail.

The wheel hub 12, brake rotor 14, and tone ring 16 are mounted togetherfor rotation about an axis 18. The wheel hub 12 is mounted to anotherwheel component (not shown), such as a wheel rim, with a plurality offasteners 20. The wheel hub 12 includes a central bore 22 that surroundsa non-rotating axle component (not shown), such as a spindle forexample. The wheel hub 12 is rotatably supported by a pair of bearings24 that are positioned between the wheel hub 12 and the spindle.

The brake rotor 14 includes a first set of mounting bosses 26 and asecond set of mounting bosses 28 that are both circumferentially spacedabout the axis 18 (FIG. 2). The first 26 and second 28 sets of mountingbosses are positioned in a non-overlapping relationship to each other.Thus, the first set of mounting bosses 26 is circumferentially spacedabout the axis 18 in a first pattern and the second set of mountingbosses 28 is circumferentially spaced about the axis 18 in a secondpattern that is different than the first pattern.

The tone ring 16 is mounted to the brake rotor 14 via the first set ofmounting bosses 26 and the brake rotor 14 is independently mounted tothe wheel hub 12 via the second set of mounting bosses 28. Thus, thefirst set of mounting bosses 26 provides a first mount interface betweenthe tone ring 16 and the brake rotor 14 and the second set of mountingbosses 28 provides a second mount interface between the brake rotor 14and the wheel hub 12. The first mount interface is independent from thesecond mount interface such that the brake rotor 14 is removable fromthe wheel hub 12 without having to remove the tone ring 16 from thebrake rotor 14, and such that the tone ring 16 is removable from thebrake rotor 14 without having to remove the brake rotor 14 from thewheel hub 12.

The brake rotor 14 is shown in greater detail in FIGS. 2 and 3. Thebrake rotor 14 includes an outer circumferential portion 30 thatincludes opposing braking surfaces 32 for engagement with frictionalmaterial supported by a pair of brake pads (not shown). The brake rotor14 also includes an inner circumferential portion 34 that includes anopening 36 that surrounds the wheel hub 12 (FIG. 1).

The inner circumferential portion 34 includes a generally flatdisc-shaped portion 38 that includes the second set of mounting bosses28. A wall portion 40 extends from the inner circumferential portion 34to the outer circumferential portion 30. The wall portion 40 extendsgenerally parallel to the axis 18. The wall portion 40 includes aplurality of extensions 42 that form the first set of mounting bosses26. Each extension 42 extends radially inwardly from an inner surface 44of the wall portion 40 toward the axis 18.

The extensions 42 of the first set of mounting bosses 26 each include anaperture 46 that is defined by a first center point. The first centerpoints from all of the apertures 46 are spaced from the axis by a firstradial distance R1. The second set of mounting bosses 28 includes aplurality of apertures 50 that are formed within the disc-shaped portion38. Each aperture 50 is defined by a second center point. The secondcenter points from all of the apertures 50 are spaced from the axis by asecond radial distance R2. In the example shown, the first R1 and secondR2 radial distances are different from each other to facilitateindependent mounting for the tone ring 16 to the brake rotor 14, and forthe brake rotor 14 to the wheel hub 12. In the example shown in FIG. 2,the first radial distance R1 is greater than the second radial distanceR2, however, an opposite configuration, with the second radial distanceR2 being greater than the first radial distance R1, could also be used.Further, the patterns of the apertures could be positioned such that thefirst R1 and second R2 radial distances are approximately equal.

As shown in FIG. 1, the apertures 46 for the first set of mountingbosses 26 receive a first set of fasteners 52 (only one is shown) toattach the tone ring 16 to the brake rotor 14. The apertures 50 for thesecond set of mounting bosses 28 receive a second set of fasteners 54(only one is shown) to attach the brake rotor 14 to the wheel hub 12.Because the apertures 46 for the first set of mounting bosses 26 do notoverlap the apertures 50 for the second set of mounting bosses 28installation of the first 52 and second 54 sets of fasteners do notinterfere with each other.

The tone ring 16 is shown in greater detail in FIGS. 4 and 5. The tonering 16 includes an outer circumferential portion 60 that includes aplurality of slots 62 that are circumferentially spaced about the axis18. The slots 62 cooperate with other wheel speed sensor components (notshown) to measure and monitor wheel speed as known. The outercircumferential portion 60 includes a ring-shaped body 64 that includesa center opening 66. When mounted to the wheel hub 12 the center opening66 surrounds the spindle.

The tone ring 16 also includes a plurality of tabs 68 that extendradially inwardly from the outer circumferential portion 60. Each tab 68includes a support portion 70 that extends transversely relative to thering-shaped body 64. The support portions 70 axially extend in adirection along the axis 18. From an outer end of each support portion70 extends a mount portion 72. The mount portions 72 each include anaperture 74 that is aligned with a corresponding aperture 46 on theextensions 42 of the first set of mounting bosses 26.

The apertures 74, 46 receive the first set of fasteners 52 to attach thetone ring 16 to the brake rotor 14 as shown in FIG. 6. The brake rotor14 includes recessed area 76 into which the ring-shaped body 64 extends.

The wheel hub 12 includes a plurality of apertures (not shown) that arealigned with the apertures 50 formed in the disc-shaped portion 38. Theapertures 50 in the disc-shaped portion 38 and the apertures in thewheel hub 12 receive the second set of fasteners 54 to attach the brakerotor 14 to the wheel hub 12. To facilitate assembly, the tone ring 16can first be attached to the brake rotor 14 to form a brake rotor andtone ring sub-assembly. The brake rotor and tone ring subassembly canthen be attached to the wheel hub 12 as a unit.

This unique configuration provides separate pieces for the tone ring 16and brake rotor 14, which allows the tone ring 16 to be fabricated froma different material than the brake rotor 14. This provides weightsaving, material, and manufacturing benefits. Also, as described above,access is provided to the second set of mounting bosses 28 to remove thebrake rotor 14 from the wheel hub 12 without having to remove the tonering 16 from the brake rotor 14, in addition to allowing removal of thetone ring 16 without having to remove the brake rotor 14 from the wheelhub 12. This significantly facilitates maintenance, inspection, andcleaning operations for the various components.

Although a preferred embodiment of this invention has been disclosed, aworker of ordinary skill in this art would recognize that certainmodifications would come within the scope of this invention. For thatreason, the following claims should be studied to determine the truescope and content of this invention.

1. A wheel assembly comprising: a wheel hub defining an axis ofrotation; a brake rotor having a first mount interface comprising afirst plurality of apertures to receive a first set of fasteners tosecure said brake rotor to said wheel hub, and wherein said brake rotorincludes a second mount interface comprising a second plurality ofapertures to receive a second set of fasteners, said second mountinterface being independent of said first mount interface; and a tonering mounted to said brake rotor via said second mount interface.
 2. Thewheel assembly according to claim 1 wherein said first and said secondplurality of apertures have a non-overlapping relationship with eachother.
 3. The wheel assembly according to claim 1 wherein said first andsaid second plurality of apertures are non-coaxial.
 4. The wheelassembly according to claim 1 wherein said brake rotor and said tonering remain attached to each other via said second mount interface assaid brake rotor is removed from said wheel hub at said first mountinterface.
 5. The wheel assembly according to claim 1 wherein said tonering is separably removable from said brake rotor via said second mountinterface while said brake rotor remains attached to said wheel hub atsaid first mount interface.
 6. The wheel assembly according to claim 1wherein said brake rotor and said tone ring remain attached to eachother via said second mount interface as said brake rotor is removedfrom said wheel hub at said first mount interface and wherein said tonering is separably removable from said brake rotor via said second mountinterface while said brake rotor remains attached to said wheel hub atsaid first mount interface.
 7. The wheel assembly according to claim 1including a third plurality of apertures formed within said tone ring,said third plurality of apertures being aligned with said secondplurality of apertures when said tone ring is attached to said brakerotor at said second mount interface.
 8. The wheel assembly according toclaim 1 wherein said brake rotor includes an inner circumferentialportion with an opening surrounding an outer surface of said wheel hub,an outer circumferential portion defining a braking surface, and a wallportion interconnecting said inner circumferential portion with saidouter circumferential portion, and wherein said first plurality ofapertures are formed within said inner circumferential portion and saidsecond plurality of apertures are formed within said wall portion. 9.The wheel assembly according to claim 8 wherein said innercircumferential portion comprises a generally flat disc-shaped portionwith said first plurality of apertures extending through said generallyflat disc-shaped portion, each of said first plurality of aperturesbeing spaced apart from each other about said axis of rotation.
 10. Thewheel assembly according to claim 8 wherein said wall portion extends ina direction generally parallel to said axis of rotation with said secondplurality of apertures being formed within a plurality of discretelyspaced extensions extending radially inwardly from said wall portiontoward said axis of rotation, each of said plurality of discretelyspaced extensions including one of said second plurality of apertures.11. A method for assembling a wheel comprising the steps of: (b)mounting a brake rotor to a wheel hub at a first mount interface byinserting a first set of fasteners through a first set of aperturesformed within the brake rotor; and (b) mounting a tone ring to the brakerotor at a second mount interface that is independent from the firstmount interface by inserting a second set of fasteners through a secondset of apertures formed within the brake rotor.
 12. The method accordingto claim 11 wherein the first and the second plurality of apertures arenon-coaxial.
 13. The method according to claim 11 including unfasteningthe first set of fasteners to remove the brake rotor from the wheel hubwhile the tone ring remains fastened to the brake rotor via the secondmount interface.
 14. The method according to claim 11 includingunfastening the second set of fasteners to remove the tone ring from thebrake rotor while the brake rotor remains fastened to the wheel hub viathe first mount interface.
 15. The method according to claim 11including unfastening the first set of fasteners at the first mountinterface to remove the brake rotor from the wheel hub while the tonering remains fastened to the brake rotor during removal of the brakerotor via the second mount interface, and in an independently operablestep, unfastening the second set of fasteners at the second mountinterface to remove the tone ring from the brake rotor while the brakerotor remains fastened to the wheel hub during removal of the tone ringvia the first mount interface.
 16. The method according to claim 11wherein the wheel hub, the brake rotor, and the tone ring rotate aboutan axis of rotation and including circumferentially spacing the firstplurality of apertures about the axis of rotation and circumferentiallyspacing the second plurality of apertures about the axis of rotationsuch that the first and the second plurality of apertures have anon-overlapping relationship.